U.S. patent number 4,731,911 [Application Number 06/894,669] was granted by the patent office on 1988-03-22 for extruded closure strip carrying reactivatable adhesive layer.
This patent grant is currently assigned to Minigrip, Inc.. Invention is credited to Russell J. Gould.
United States Patent |
4,731,911 |
Gould |
March 22, 1988 |
Extruded closure strip carrying reactivatable adhesive layer
Abstract
A closure strip adapted to be bonded to a substrate comprises a
one-piece polymeric extrusion having a base surface essentially no
wider than the profile portion of the strip and wherein a plane
projected normal to and bisecting the base surface longitudinally
into two parts also bisects the profile portion into two
corresponding parts, a dormant but reactivatable adhesive layer
adhering to and along the base surface on at least one side of the
plane, so that the closure strip is adapted to be bonded to the
substrate upon reactivation of the dormant adhesive.
Inventors: |
Gould; Russell J. (Mt.
Prospect, IL) |
Assignee: |
Minigrip, Inc. (Orangeburg,
NY)
|
Family
ID: |
25403373 |
Appl.
No.: |
06/894,669 |
Filed: |
August 8, 1986 |
Current U.S.
Class: |
24/585.12;
24/DIG.39; 24/DIG.50; 383/35; 383/63 |
Current CPC
Class: |
A44B
9/16 (20130101); A44B 19/40 (20130101); B29C
66/474 (20130101); B29C 65/58 (20130101); B29C
66/1122 (20130101); B29C 66/43 (20130101); B65D
33/2541 (20130101); B29C 66/83413 (20130101); B29C
66/71 (20130101); B31B 70/8131 (20170801); B29L
2005/00 (20130101); Y10S 24/50 (20130101); Y10S
24/39 (20130101); Y10T 24/45168 (20150115); B29C
66/71 (20130101); B29K 2023/12 (20130101); B29C
66/71 (20130101); B29K 2023/06 (20130101) |
Current International
Class: |
A44B
9/16 (20060101); A44B 19/24 (20060101); A44B
19/40 (20060101); A44B 9/00 (20060101); B31B
19/00 (20060101); B31B 19/90 (20060101); B29C
65/58 (20060101); B29C 65/56 (20060101); B65D
33/25 (20060101); B65D 033/24 () |
Field of
Search: |
;24/587,576 ;206/274
;383/35,63,65 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1546433 |
|
May 1979 |
|
GB |
|
1587609 |
|
Apr 1981 |
|
GB |
|
2080412A |
|
Feb 1982 |
|
GB |
|
Other References
"BFGoodrich Plastilock Hot Melt Selector Guide" Four pages, 1982.
.
"Assembly of Fabricated Parts, Adhesive Bonding," Modern Plastics
Encyclopedia 1979-1980, pp. 418-420. .
"Assembly of Fabricated Parts, Adhesive bonding," Modern Plastics
Encyclopedia 1973-1974, pp. 480-481..
|
Primary Examiner: Sakran; Victor N.
Attorney, Agent or Firm: Hill, Van Santen, Steadman &
Simpson
Claims
I claim as my invention:
1. A closure strip adapted to be bonded to a substrate such as film
in the manufacture of reclosable bags, the closure strip having a
longitudinally extending base portion providing a longitudinally
extending base furface, and a profile portion extending
longitudinally along the base portion and having profile means
projecting in the opposite direction from that in which the base
surface faces, the base and profile portions comprising an
extrusion in one piece from a polymeric material and being shaped
cross-sectionally such that a plane projected normal to and
bisecting said base surface longitudinally into two parts also
bisects the profile portion into two corresponding parts, and
comprising:
said base surface being directly back of said profile portion and
of a width essentially no wider than said profile portion;
and a dormant but reactivatable adhesive layer adhering to and
along said base surface on at least one side of said plane, so that
the closure strip is adapted to be bonded to the substrate upon
reactivation of the dormant adhesive.
2. A closure strip according to claim 1, wherein said strip
comprises a material selected from polyethylene and polypropylene,
and said adhesive comprises a material selected from polymer rubber
resin blend, ethylene acrylic acid, and ethylene vinyl acetate.
3. A closure strip according to claim 1, wherein said base portion
surface has spaced longitudinal ribs defining a channel
therebetween and within which channel said dormant but
reactivatable adhesive is located.
Description
BACKGROUND OF THE INVENTION
This invention relates to the art of synthetic plastic resin
extruded separable fasteners and a method of making the same, and
is more particularly concerned with prefabricating such fasteners
at a high rate of production, economically and for subsequent union
with desired substrates.
As revealed in the prior art exemplified by U.S. patents, proposals
for uniting extruded separable fasteners, sometimes referred to in
the trade as zippers, have comprised joining the fastener profile
strips to a compatible extruded synthetic plastic film substrate
while both of the separately, but simultaneously extruded
components are still in a sufficiently plastic state to fuse
together, as exemplified in U.S. Pat. Nos. 3,462,332 and
4,259,133.
Another technique, as exemplified in U.S. Pat. Nos. 3,784,432 and
4,279,677, includes joining the freshly extruded profile strips to
compatible prefabricated plastic film substrate while the fastener
strip is still in a sufficiently thermoplastic state to permit
fusing the thermoplastic film which is reheated from a cold state
to accelerate the fusion.
A further technique as exemplified in U.S. Pat. No. 3,532,571
includes joining freshly extruded film to compatible prefabricated
fastener strips while the film is still in a sufficiently
thermoplastic state to permit fusing the fastener strip to the
film.
It has, of course, been longtime common practice to join
prefabricated fastener strip to prefabricated compatible plastic
film by fusion welding, as exemplified in U.S. Pat. No.
3,948,705.
A distinct advantage attributable to prefabricating profile
fastener strips and bag making plastic film resides in the fact
that because of the relatively larger section modulus of the
profile strips as compared to the section modulus of the plastic
film, the plastic film when extruded separately can be run at a
much greater speeds than the profile fastener strips. Therefore by
spooling the prefabricated fastener strips and the prefabricated
film in separate rolls, they can be fed simultaneously at desired
speed and joined together as by means of adhesive applied in a
fluent state between the elements as they are brought convergently
together, as exemplified, by U.S. Pat. Nos. 4,101,355; 4,341,575;
4,354,541 and 4,355,494. A distinct advantage of such
prefabrication and then adhesive joinder of the profile fastener
strips and the substrate is that relatively incompatible materials
may be utilized to advantage in the respective elements. For
example, a form of plastic material which will lend itself to best
advantage for extrusion of the profile strips, and will afford the
most advantageous elastic deformation separable coaction of the
fastener profiles may be utilized for that purpose, while materials
having special characteristics desirable for the end product such
as bags may be utilized in the film whether plastic or non-plastic.
The composite finished product will then be endowed with all of the
preferred characteristic in both the fastener and the
substrate.
With all of the advantages inherent in adhesively securing
prefabricated elastically deformable separable profile fastener
strips to prefabricated film substrate, there is still room for
substantial improvement in the adhesive attachment technique. A
disadvantage of adhesive attachment as heretofore proposed has been
the requirement for extremely accurate control of the fluent
adhesive, both as to volume at point of application, temperature
gradients during application, tackiness, machine down time,
necessarily close attention to the adhesive applicators, avoidance
of adhesive spray machine foul-up, and the like. Therefore, onsite
adhesive joinder of the profile fastener strips and the substrate
has placed a heavy burden on the machine operators to maintain all
of the critical parameters necessary for successful results. This
has been particularly the case when the adhesive attachment is
combined with a form fill operation as described in U.S. Pat. No.
4,355,494, where the advantage of shipping finished film and
finished fastener separately and thereby saving space as well as
reducing spool change-over because of larger spools, are then lost
due to the relatively complex liquid adhesive applying
operation.
It has been proposed in published U.K. Patent Application
2,080,412A to provide fastener strips having sidewardly extending
attachment webs carrying heat reactivatable adhesive. However, the
fastener strips having such attachment webs are more costly to
produce than a web-free fastener strip such as disclosed in British
Pat. No. 1,587,609. Neither of these British publications has an
adequate teaching of how to prefabricate fastener strips with
reactivatable adhesive, and in particular such fastener strips
without side attachment webs.
SUMMARY OF THE INVENTION
It is accordingly an important object of the present invention to
overcome the disadvantages, drawbacks, inefficiencies, limitations,
shortcomings, and problems inherent in prior extruded prefabricated
resiliently flexible fastener plastic profile strips, and to
provide a new and improved fastener of this kind carrying
reactivatable adhesive for bonding the strips to a substrate.
To this end, the present invention provides a closure strip adapted
to be bonded to a substrate such as film in the manufacture of
reclosable bags, the closure strip having a longitudinally
extending base portion providing a longitudinally extending base
surface, and a profile portion extending longitudinally along the
base portion and having profile means projecting in the opposite
direction from that in which the base surface faces, the base and
profile portions comprising an extrusion in one piece from a
polymeric material and being shaped cross-sectionally such that a
plane projected normal to and bisecting said base surface
longitudinally into two parts also bisects the profile portion into
two corresponding parts, and comprising said base surface being
directly back of said profile portion and of a width essentially no
wider than said profile portion, and a dormant but reactivatable
adhesive layer adhering to and along said base surface on at least
one side of said plane, so that the closure strip is adapted to be
bonded to the substrate upon reactivation of the dormant
adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the present invention
will be readily apparent from the following description of certain
representative embodiments thereof, taken in conjunction with the
accompanying drawing, although variations and modifications may be
effected without departing from the spirit and scope of the novel
concepts embodied in the disclosure, and in which:
FIG. 1 is an enlarged sectional elevational detail view showing a
synthetic resin, resiliently flexible separable fastener comprising
an assembly of complementary profile strips and provided with base
surface adhesive pursuant to the present invention, by which the
fastener is adapted to be secured to substrates;
FIG. 2 is a schematic perspective view demonstrating a preferred
method and apparatus for producing fasteners in accordance with the
present invention.
FIG. 3 is an enlarged fragmentary sectional detail view taken
substantiallly along the line III--III of FIG. 2;
FIG. 4 is a schematic elevational view showing a modified mode of
applying adhesive to the fastener strips;
FIG. 5 ia a view similar to FIG. 1, but showing a modification;
FIG. 5A is a view similar to FIG. 5 but showing a modification;
FIG. 5 is a view similar to FIG. 1 but showing another modified
form of the resiliently flexible separable fastener pursuant to the
present invention;
FIG. 7 is a schematic perspective view similar to FIG. 2 but
showing a modification in the method and apparatus for producing
the fastener of FIG. 6;
FIG. 8 is an enlarged fragmentary sectional detail view taken
substantially along the line VIII--VIII of FIG. 7; and
FIG. 9 is a view similar to FIG. 4, but applicable to making the
fastener of FIG. 6.
DETAILED DESCRIPTION
Referring to FIG. 1, an elastically deformable, resiliently
flexible separable fastener 10 comprises preferably identical,
extruded plastic strips 11 of the plural interlocking rib and
groove type. Each of the fastener strips 11 has a set of profiles
12 extending longitudinally along the strip, and which are of the
separably interlocking hooked rib and groove form. By way of
example the profiles 12 provide complementary grooves wherein the
hooks of the rib profiles of the set on one of the fastener strips
interengage within the complementary grooves of the profile set on
the companion or mating fastener strip.
Each of the fastener strips has a base surface 13 carrying a
dormant but reactivatable adhesive 14 by which the base surface 13
is adapted to be secured to a substrate 15, such as film in the
manufacture of reclosable bags, when the adhesive is reactivated,
that is converted from a generally non-sticky, dormant freely
handleable state into a sticky, adherent operational state. It will
be understood that the separable fastener 10, although shown for
illustrative purposes in an enlarged form, may be produced in any
desirable size suitable for the intended purpose, and in particular
for making bag material.
As shown, the fastener strips 11 are advantageously free from
lateral flanges, because according to the present invention such
flanges are unnecessary. This not only saves plastic material, but
also permits a much greater rate of production of the plastic
fastener strips 11 carrying the profiles 12, because a greater
number of the strips 11 can be simultaneously extruded through an
extrusion die. Because of the lack of lateral webs on the profile
strips 11, the extrusion orifices can be fairly closely spaced, and
a greater multiple of fasteners can be extruded at one time. For
example a fastener, or lock, adapted for small bag making, and
provided with side webs may require at least six times as much
space on the die per lock, as compared to a similar lock without
webs. Accordingly, a die can easily accommodate six times as many
web-free locks without disturbance in the flow of plastic through
the extruder, whereas to attempt to extrude the same number of
locks wherein the profile strips have attached webs would be
extremely difficult to control. This achieves significant
production economy.
Another advantage of webless fastener profile strips is that
10,000' to 15,000' storage and handling spools become readily
available, whereas the same size of profile strips with lateral
webs must generally be limited to about 6,000' per spool, having
regard to a spool size that can be readily handled. Spools with
greater footage of fastener profile strip require fewer changes in
a production run where the strip is joined to the substrate, and
hence less spool change down-time is lost in production.
By way of emphasizing the particular construction and relationship
of the elements of each of the closure or fastener strips 11, it
may be noted that each base portion and more particularly the base
surface 13 of each strip 11 is located in alignment directly back
of the profile portion of each strip, the profile portion
projecting in the opposite direction from that in which the base
surface of the strip faces. The base portions and the profiles are
extruded in one piece from a polymeric material and the strip in
each instance is shaped cross-sectionally such that a plane P
normal to and longitudinally bisecting the base surface 13 also
bisects the profile portion into two parts. The dormant but
reactivatable adhesive 14 adhering to the base surface 13 may be on
both portions of the base surface 13 bisected by the plane P, or
may be located on the base surface 13 only along one side of the
plane P. The width of the base surface at either side of the plane
P may be varied to suit many particular circumstances, especially
where the reactivatable adhesive 14 is to be carried by the surface
13 but only on one side of the plane P.
As exemplified in FIG. 2, a compact four orifice extrusion die 18,
having two sets of profile strip orifices 19, is thereby adapted to
produce simultaneously two complete fastener assemblies 10.
Preferred thermoplastic materials from which the profile strips are
adapted to be extruded comprise polyethylene having a melting point
of from 230.degree. F. to 270.degree. F., polypropylene having a
melting point on the order of 345.degree. F., and the like.
According to the present invention, the adhesive 14 is adapted to
be applied to the fastener strip base surfaces 13 during extrusion
of the strips 11. In one useful mode the adhesive 14 comprises a
so-called hot melt adhesive selected from ethylene vinyl acetate,
ethylene acrylic acid, polymer rubber resin blend, and the like,
having a selected bonding fusion range of from 175.degree. F. to
260.degree. F. The bonding fusion temperature of the adhesive
should be sufficiently less than the melting point of the fastener
profile strip material to which it is applied to permit the
reaching of bonding fusion of the adhesive 14 from a cold generally
dormant condition, by application thereto of heat at a temperature
which will not cause softening deformation or any other
deterioration of the plastic material of the fastener profile
strip.
In another useful mode, the adhesive 14 may be of a type which
after it has been applied to the fastener strip base 13 is adapted
to set to a dry dormant, inactive state from which it can be
reactivated by applying a suitable quick acting solvent to its
substrate-engageable surface just before the fastener strip joins a
substrate to which it is adhesively secured by the reactivated
adhesive.
Conveniently, application of the adhesive 14 to the base surfaces
13 of the profile strips 11 is adapted to be effected at the
orifices 19, and in a useful mode by coextrusion through the
orifices 19 in the die 18, as best visualized in FIGS. 2 and 3. For
this purpose, the adhesive 14 in a fluent state is supplied from a
supply source 20 for each of the profiles strips 11. From the
supply source 20 the fluid adhesive is conducted through a passage
21 in each instance to that area of each of the die orifices 19
which shapes the respective base surface 13 of the profile strip
11. As all of the plurality of profile strips 11 are simultaneously
extruded, the adhesive 14 that is applied as a layer to the
respective profile strip base surfaces 13 is carried along on the
surfaces 13 as the extruded strips emerges from the die 18.
Thence, the strips 11 carrying the adhesive thereon pass to and
through means defining a curing zone in this instance comprising a
chilling chamber 22 (FIG. 2). There the profile strips 11 are
firmed and set, and the adhesive layers 14 are concurrently with
the curing of the strips set and cured to a dormant state on the
base surfaces 13 but from which dormant state the adhesive can be
reactivated later on for bonding to the substrates 15.
In the compact arrangement of FIG. 2, all of the orifices 19 are
oriented to form the back surfaces 13 in a common plane, that is
facing toward the delivery ports or orifices of the adhesive
delivery passages 21. Thus the profiles 12 of the extruded strips
11 all face in the opposite direction. As shown all of the back
surfaces 13 of all of the fastener strips 11 face upwardly and all
of the profile ribs and grooves 12 face downwardly. By preference
the profiled fastener strips 11 are extruded in adjacent pairs so
that downstream from the extrusion orifices 19, and after leaving
the curing chamber 22, the pairs of complementary strips 11 can be
assembled together by relatively reorienting the pairs of fastener
strip and interengaging the profiles 12. For example, means may be
provided for twisting the corunning profile strips 90.degree.
toward one another so that the profiles 12 face each other, and
then pushing the strips toward one another to interengage the
profiles. On the other hand, one of the profile strips may be
twisted 180.degree. relative to the companion profile strip and
then the strips joined by pressing the companion strips together
for interengaging the profiles 12. For the latter maneuver, strip
deflecting and twisting means desirably comprises a series of
cooperatively related pairs of rollers comprising a first pair of
rotary pinch rolls 23, one of which engages the cured
adhesive-carrying back surface 13 of one of the fastener strips 11
and the other of which engages the tips of the profile ribs 12.
That initiates not only a twisting of the engaged strip but also
deflection of the strip toward the profiles 12 of the companion
strip. Thereafter, one or more second pairs of pinch rolls 24,
which may engage the sides of the strip 11 being twisted and
deflected, complete the turning of the strip into an inverted
orientation with the profiles 12 of the inverted strip aligned for
interengagement with the profiles 12 of the companion strip which
has remained in the orientation in which it was extruded while
corunning with the deflected and twistingly reoriented strip.
Immediately downstream from this reorientation of the strips 11,
the companion strips are pressed together as by means of pinch
rolls 25 into closed fastener assembly relation. Downstream from
the interlocked joining of the fastener strips into closed fastener
relation, the continuously running fastener assemblies are adapted
to be wound into storage rolls 27 of suitable size for subsequent
handling and processing.
Any suitable driving means 26 may drive the pinch rolls 23, 24 and
25 and the spooling means for the storage rolls 27, in properly
coordinated relation.
If preferred, the adhesive layers 14 may be applied to the base
surfaces 13 of the fastener profile strips 11 during extrusion of
the strips, but immediately downstream from the extrusion die 18'
(FIG. 4) by applying the adhesive through respective nozzles 28
communicating with adhesive source 20' through passage means 21'.
In this arrangement, similarly as in the arrangement where the
adhesive 14 and the strips 11 are coextruded, the adhesive and the
profile strips are concurrently set into cured condition, and then
assembled similarly as has already been described. Application of
the adhesive by means of the nozzles 28 is also well suited for
applying an adhesive which is reactivatable by means of a solvent
where the adhesive when applied is in a fluent state by reason of a
solvent vehicle so that the extruded heat of the fastener strips to
which it is applied will accelerate driving off the solvent from
the adhesive with the curing of the adhesive and the fastener
strips then completed concurrently.
Inadvertent, unintended adherence to any surface other than a
chosen substrate may sometimes occur by reason of the adhesive 14
possibly having some latent tackiness for any reason after the
curing step, or possibly tending to reactivate prematurely when
subjected to inadvertent or careless adverse environmental handling
or exposure. To avoid such occurence, the arrangement disclosed in
connection with FIG. 5 may be employed, wherein the adhesive 14' is
applied to the back surface 13' of the fastener strip 11' in each
instance within a shallow channel defined on the back surface 13'
between transversely spaced spacer and retainer ribs 29 extending
longitudinally and integral with the retainer strip 11' and
defining the opposite sides of the adhesive receiving channel. The
ribs 29 are only slightly, if any, higher than the layer of
adhesive 14'.
At least two functions are attributable to the ribs 29. In one
function the ribs 29 serve as spacers to maintain out of unintended
adhering contact with the adhesive 14' any object at least as wide
as the strips 11, such for example as the back of the companion
fastener strip in the fastener assembly 10 rolled thereon in a
storage spool, or storage or shipping packing material, or guide
surfaces with which the strip may have to be in contact in an
assembly operation with substrate. To enhance the effectiveness of
the spacer ribs 29, the base surface 13' may be formed slightly
concave in transverse direction and the layer of adhesive 14'
applied to the concave base surface within the channel to a
substantially uniformed depth, so that the surface of the set
adhesive 14' will also be transversely concave conforming to the
channel base surface. Thereby the adhesive 14' will be maintained
out of contact with the surface of any object bridging across the
spacers 29. However, by reason of the shallow depth of the adhesive
containing channel and the shallow height of the ribs 29, only
normally moderate relative assembly pressure between the fastener
assembly back surfaces and substrate 15' with the adhesive 14'
reactivated, will result in thorough adhesion of the fastener
strips to the substrate. Where the material of the fastener strips
11' is of sufficient elasticity, pressing against the substrate 15'
in the bonding operation will cause uniform deflection of the base
surface 13' toward the substrate for bonding by the adhesive 14'.
Where the material of the fastener strips 11 is relatively stiff,
it may be desirable to yieldably deform the substrate 15', such as
a bag making film or the like into the shallow adhesive containing
channel provided by the back surface 13' between the spacers 29.
Because of the shallow nature of the channel and the spacers 29
deformation of the bonded substrate 15' may be hardly perceptible,
and if perceptible unobjectionable for most purposes.
Another function of the spacers 29 is to confine the adhesive 14'
against spreading beyond the side edges of the fastener strips 11'.
This avoids a possibly unsightly dross condition alongside the bond
joint should there be any tendency for the adhesive 14' in
reactivated fluidized or tackified condition to spread laterally
from the bond joint under pressure during the bonding
operation.
Where it is desired to provide the adhesive 14' only along a
longitudinal area on a portion of the back or base surface 13', the
arrangement shown in FIG. 5A may be utilized wherein one of the
shallow rib spacers 29 extends longitudinally along one edge of the
base surface 13', while a second one of the spacers 29 extends
longitudinally along an intermediate line on the base surface 13'.
For example, where it is desired to have the reactivatable dormant
adhesive 14' on only one half of the surface 13', the intermediate
spacer 29 may extend along a substantially medium longitudinal line
on the base surface.
On reference to FIG. 6, an elastically deformable, resiliently
flexible separable fastener 30 is of the type comprising a male
profile 31 and a female profile 32 which are of the separably
interlocking hooked rib and groove form, shown, by way of example,
as comprising a generally arrowhead cross-section on the male
profile 31 adapted to interhook with a complementary channeled
formation of the female profile 32. Each of the profile strips 31
and 32 has opposite its interlocking profile formation a base
surface, comprising a base surface 33 on and extending along the
male profile 31, and a base surface 34 extending on and along the
female profile 32. Each of the fastener base surfaces 33 and 34
carries a reactivatable adhesive 35 by which the respective base
surfaces are adapted to be secured to substrate 37 when the
adhesive 35 is reactivated, that is converted from a generally
non-sticky, dormant, freely handleable state into a sticky,
adherent operational state. It will be understood that the fastener
30, although shown for illustrative purposes in an enlarged form,
may be produced in any desirable size suitable for the intended
purpose, and in particular for making bag material. As will be
observed, the fastener profile strips 31 and 32 are advantageously
free from lateral flanges, for the advantageous reasons heretofore
described.
As exemplified in FIG. 7, an advantageous fastener strip
prefabrication extrusion arrangement is adapted to have a
multi-orifice extrusion die 38 adapted for simultaneously extruding
profile fastener strip for as many as four fastener assemblies
simultaneously. Thermoplastic material is supplied under extrusion
pressure to the die 38 by means of an associated extruder 39 which
may be of any preferred form adapted for this purpose. Conveniently
four companion pairs, comprising a total of eight extrusion
orifices will provide for four of the fastener assemblies 30. For
this purpose four male profile strip extrusion orifices 40 are
located in the die 38 in alignment with four respective female
fastener strip forming orifices 41. As shown, the orifices 40 are
vertically aligned in superjacent spaced relation to the orifices
41.
As shown in FIGS. 7 and 8, adhesive 35 is adapted to be applied to
the fastener strip base surfaces 33 and 34 by supplying fluent
adhesive from a supply source 43 through ducts or passages 44 which
deliver the adhesive 35 in the proper volume and width to the
respective base surfaces 33 and 34. This coextrusion of the
fastener strip plastic and adhesive is especially suitable for heat
reactivatable adhesive.
If it is preferred to apply the adhesive layers 35 to the
respective base surfaces 33 and 34 of the profile strips 31 and 32,
respectively, during extrusion of the strips but immediately
downstream from the extrusion die 38' (FIG. 9), the adhesive 35 is
adapted to be applied through respective nozzles 45 which
communicate with the respective adhesive sources 43' through the
passage means 44'. When thus applied, the adhesive 35 may be of
either the hot melt type or solvent fluidized type. In either
event, the adhesive and profile strips are then concurrently set
and cured by running the same through a curing chamber 47 which
receives the adhesive equipped corunning fastener strips 31 and 32
adjacently downstream from the extrusion die 38. After the cured
fastener strips with the cured adhesive thereon leave the curing
chamber 47, the fastener strips in vertical alignment pass between
pinch rolls 48 which squeeze the fastener strips toward and into
assembly with one another wherein the male and female profiles are
separable interconnected. Downstream from the fastener strip
assembly pinch rolls 48, the fastener assemblies 30 are wound into
storage rolls 49 of suitable size for subsequent handling and
processing. It will be understood that the pinch rolls 48 and the
usual cores or spools on which the rolls 49 are wound are adapted
to be driven in any suitable manner for advancing the extruded
profile strips from the extrusion die 38 at a speed compatible with
the extrusion speed.
In use, the adhesive-carrying profile strips of the fastener
assemblies 10 or 30, as the case may be, are adapted to be joined
to the substrates 15 or 37 by reactivating the dormant adhesive 14
or 35 at a proper temperature below the softening point of the
plastic material of the associated profile strips, as the adhesive
carrying base surfaces are being pressed into adherence with and
bonded to the substrate. Where the adhesive carried by the fastener
strip bases is of the solvent reactivatable type, the solvent may
be applied in any suitable manners such as by means of a suitable
applicator, for example an applicator roll immediately upstream
from the point at which bonding is effected.
It will be understood that variations and modifications may be
effected without departing from the spirit and scope of the novel
concepts of this invention.
* * * * *